Allow PHP-Only Block Registration

[wildworks]

This ticket tracks the backport of PHP files for the following Gutenberg updates:

​https://github.com/WordPress/gutenberg/pull/75543

If the supports.auto_register supports.autoRegister flag is opted in when executing register_block_type(), those blocks will be exposed as the autoRegisterBlocks block editor setting.

The editor will use that setting to generate the blocks using server-side rendering.

Trac ticket:

## Use of AI Tools

@oandregal, Based on ​your suggestion, I've added server-side type checking in 658b7af6ed40562da9aabaaad86c4b66d1e75525. I'd be happy to see if this is what you wanted.

@t-hamano thank you, that's great :)

@oandregal Thanks for the review! After committing this PR to core, I would like to backport similar changes to Gutenberg.

[wildworks]

In 61661:

Block Supports: Add autoRegister support for PHP-only block registration.

Introduces block support for PHP-only block registration, enabling developers to register blocks in PHP without requiring JavaScript registration code.

When a block declares 'supports' => array( 'autoRegister' => true ) along with a render callback, it is exposed to the client-side via a JavaScript global variable and registered automatically.

Example usage:

register_block_type(
	'my-plugin/example',
	array(
		'title'           => 'My Example Block',
		'attributes'      => array(
			'title' => array(
				'type'    => 'string',
				'default' => 'Hello World',
			),
			'count' => array(
				'type'    => 'integer',
				'default' => 5,
			),
		),
		'render_callback' => function ( $attributes ) {
			return sprintf(
				'<div %1$s>%2$s: %3$d items</div>',
				get_block_wrapper_attributes(),
				esc_html( $attributes['title'] ),
				$attributes['count']
			);
		},
		'supports'        => array(
			'autoRegister' => true,
		),
	)
);

Props mcsf, oandregal, ramonopoly, westonruter, wildworks.
Fixes #64639.

[butterflymedia]

This is THE FIRST block-editor-related good news since Gutenberg was first implemented.

This is also a nice, extended, resource of some additional blocks being implemented using this method:

​https://getbutterfly.com/php-only-block-registration-in-wordpress/

[audrasjb]

This will need a dedicated dev note.
@wildworks are you gonna handle that task?

And of course it's worth a mention in the Field Guide.

[wildworks]

A dev note for this feature is being tracked on the Gutenberg side and has just been published.

​https://make.wordpress.org/core/2026/03/03/php-only-block-registration/